Perhaps this page at Apple will help. The instructions worked for me in Ventura.
1. Have the Screen Saver item in System Prefs open.
2. Press Shift + Command + 5 to open the screen shot settings details.
3. Set the delay to 10 seconds.
4. Click the "Full Screen" icon.
5. Select the Screen Saver you want to capture.
6. Press the "Preview" button in the Screen Saver Prefs.
7. Wait for the 'captured' sound and press any key to see the tiny, captured image in the lower, right-hand corner of your screen.
8. use your favorite disk/file search app to look for a .png file with a name starting with "Screenshot". It may be right on your Desktop. My testing created a file named:
"Screenshot 2024-02-13 at 10.13.30 AM.png"
Screenshots are saved as .png files and screen recordings are saved as .mov files. Filenames begin with “Screenshot” or “Screen Recording” and include the date and time.